In the Garden
Amy Jordan, Special to The Gazette
Thursday, August 28, 2008
Rhizomatous Tall Fescue (RTF) is available at garden centers and hyped as a good choice for a lawn because of its ability to send out rhizomes.
Rhizomes are underground stems that are useful in a plant’s ability to spread, a trait that could help with turf recovery. But does rhizomatous tall fescue perform as well as the marketing suggests?
Many other grasses produce rhizomes, some very aggressively, like Bermuda grass. Tall fescue is the most commonly planted turfgrass in our area because it typically performs the best in our climate. Tall fescue is a bunch-type grass that sends out tillers, or mini-rhizomes and can slowly spread or thicken a lawn.
Turfgrass researchers at Kansas State University have been testing RTF cultivars since 2006. The results so far indicate that RTF cultivars do not produce rhizomes or spread more quickly than any other tall fescue variety in the trial. The research will continue, but at this point RTF seems to perform about the same as other tall fescue cultivars.
Early fall is the best time of year for lawn renovation using a cool season grass like tall fescue because environmental conditions are favorable and weed competition is much lower than in spring. Also, the soil temperatures are warmer than in the spring, resulting in more rapid germination of seed.
Weeds should be removed prior to seed bed preparation. This could be done manually or using an herbicide. This should be done at least 2 weeks before planting. A broadleaf weed killer could be used on weeds such as dandelion, spurge, or knotweed. A non-selective herbicide such as glyphosate (Roundup, Kleen-up, or others) can be used on grassy weeds such as bermudagrass, foxtail, crabgrass and orchardgrass. This will kill most green vegetation it contacts, so be careful to apply only to those areas and plants you want killed. Be sure to follow label directions on how long to wait before seeding.
A turf type tall fescue blend contains several cultivars that are bred to green up quicker in the spring, hold a richer color, have a smoother texture and finer leaf blade. A blend capitalizes on the strengths of each variety, while minimizing the weaknesses.
Carefully inspect the grass seed label to know what you are buying. One of the most important things to look for is listed as “ percent other crop”. Orchardgrass and rough bluegrass are perennial grassy weeds that are both are listed as “other crop” seed. Even a small amount could be problematic.
For example, if a bag of tall fescue seed contained 0.5 percent orchardgrass, the buyer would end up “planting” 12 to 16 orchardgrass seeds per square foot! If your expectations are high for the area you are planting, you would want the “other crop” to be as close to zero as possible. Good quality seed will often have 0.01 percent “other crop” or less.